In general, an external data storage apparatus of which we make use includes a hard disc or a memory device, an external case in which the hard disc, memory device or the like is held, and an interface interfaced with a personal computer.
Currently, this external data storage apparatus has a simple configuration, and is in wide use due to a compact size, easy portability, and convenient storage and management of the data on the basis of the connection with the personal computer.
However, the existing external data storage apparatuses have an advantage in that, after they are connected with the personal computer or another storage medium through which the data can be input and output, the data is very easily and simply input and output by operating a keyboard, whereas they have a disadvantage in that, because the data can be easily input and output by any one as described above, the stored data can be easily exposed to another person due to loss or careless management.
For example, the existing external data storage apparatuses have another disadvantage in that the security for personal information is very weak, because anyone can be read out the data recorded in the external data storage apparatuses by separating only the hard disc from the case and then connecting the hard disc to the personal computer, and because such data can be damaged on purpose.